Current approaches to creating mixed inhibitors of metal corrosion in acid solutions and possible pathways of their action on the corrosion process are reviewed. Quantitative approaches to assessing the mutual effect of the components of mixed inhibitors are analyzed, and criteria for the synergism of their action are discussed. The high efficiency of ternary mixed inhibitors based on triazole derivatives in the protection of different steels in high-temperature acid solutions (t = 100–180°C) and solutions of acid mixtures containing Fe(III) salts is shown. Important practical advantages and disadvantages of the different groups of inhibitors of metal corrosion in acidic media are discussed. Data on protecting metals in acidic media with so-called green inhibitors are summarized, and the prospects and discrepancies associated with their practical application are discussed. The need to search for technologies allowing the use of inhibited acid solutions that meet the environmental requirements of current production while simultaneously allowing for the hazard of solutions of the acids is shown.